import re
from pathlib import Path

class SvgColorParser:
    def __init__(self, filepath):
        self.filepath = Path(filepath)
        self.content = self.filepath.read_text(encoding="utf-8")
        self.colors = {} # tag -> hex
        self.history = [] # list of contents for undo
        self.redo_history = []
        self._parse()
        
    def _parse(self):
        # Find the <style id="current-color-scheme">...</style> regardless of attribute order
        style_match = re.search(r'<style[^>]*?id="current-color-scheme"[^>]*>(.*?)</style>', self.content, re.DOTALL)
        if style_match:
            style_content = style_match.group(1)
            # Find classes e.g. .ColorScheme-Text { color:#232629; }
            class_matches = re.finditer(r'\.(ColorScheme-[a-zA-Z0-9]+)\s*\{\s*color:\s*(#[a-fA-F0-9]{3,6})', style_content)
            self.colors = {m.group(1): m.group(2) for m in class_matches}
            
    def update_color(self, tag, new_hex):
        if tag not in self.colors: return
        old_hex = self.colors[tag]
        self.history.append(self.content)
        self.redo_history.clear()
        
        # Globally replace the exact hex string, case insensitive
        # We need to compile a regex for the old hex.
        hex_pattern = re.compile(re.escape(old_hex), re.IGNORECASE)
        self.content = hex_pattern.sub(new_hex, self.content)
        
        self.colors[tag] = new_hex
        self.save()
        self._parse() # re-parse to ensure consistency
        
    def save(self):
        self.filepath.write_text(self.content, encoding="utf-8")
        
    def undo(self):
        if self.history:
            self.redo_history.append(self.content)
            self.content = self.history.pop()
            self.save()
            self._parse()
            return True
        return False
        
    def redo(self):
        if self.redo_history:
            self.history.append(self.content)
            self.content = self.redo_history.pop()
            self.save()
            self._parse()
            return True
        return False